A. Field of the Invention
The device of the present invention relates to a new and improved seal for preventing the escape of particles of material during loading of material onto a conveyor belt.
B. Description of the Prior Art
Transportation of material such as sand, grain or similar material is economically accomplished over short distances by conveyor belt systems. Typically, such a system includes a hopper containing the material and a chute for depositing the material from the hopper onto a conveyor belt. The material is then transferred by the conveyor belt to another location.
To prevent wear of the belt, it is spaced a short distance, or by a gap, from the bottom of the chute. Accordingly, upon depositing material from the chute onto the conveyor belt, dust or particles of the material such as fines may escape through the gap due to the turbulence created below the chute. These escaping particles can create an undesirable atmospheric condition, and interfere with moving parts of the conveyor system, causing jamming or shutdown of the equipment and requiring extensive cleaning.
To prevent or reduce the amount of escaping particles of material, prior art systems employ skirt boards that are secured to the chute by bolts or similar fasteners and extend from the chute to within a short distance of the conveyor belt. The skirt boards block or cover the gap between the bottom of the chute and the upper surface of the belt thereby reducing the escape of materials. In addition, the skirt board may extend downstream a short distance from the chute to assist in orientation of the material onto the center of the conveyor belt.
A gap between the bottom of the prior art skirt boards and the conveyor belt, however, is desirable since the prior art skirt boards are fabricated from discarded conveyor belts or similar rubber material, and may be of a durometer hardness substantially the same as the conveyor belt. Accordingly, the skirt board should not contact the conveyor belt during operation since to do so would result in rapid wear of both the belt and the skirt board. The small gap between the bottom edge of the skirt board and the upper surface of the belt, while reducing belt wear, allows particles of material to escape. Consequently, although the problem created by the dust or particles of material is reduced, a significant amount of material can still escape.
In addition, even with the small gap provided, material may become lodged between the bottom of the skirt boards and the upper surface of the belt resulting in wear of the skirt boards and belt. The skirt boards require repeated adjustment to maintain the desired gap, and also require periodic replacement. Adjustment and replacement are difficult because the skirt boards are held in place by bolts or other fasteners.